Here, using pair-matched wild-type p53 CDDP-sensitive (OV2008) and -resistant (C13*) cells, and p53-compromised CDDP-resistant cells (A2780cp, OCC-1, OVCAR-3 and SKOV3), we have demonstrated (i) the existence of site-specific differences in phospho-Ser-Chk1 content between sensitive and resistant cells in response to CDDP; (ii) PPM1D, but not phosphoinositide-3-kinase-related kinase Ataxia Telangiectasia and Rad3 related protein (ATR), is important in the regulation of CDDP-induced Chk1 activation and OVCA cell chemosensitivity; (iii) PPM1D downregulation sensitizes resistant cells to CDDP primarily by activating Chk1 and p53.
In this study, we examined PC expression in six normal ovarian surface epithelium (OSE) cultures, nine primary ovarian cancer (OC) cultures, and three established OC cell lines (Hey, HeyC2, and OCC-1).